In surgery, for example, increasing use is being made of computer-based systems that provide information to a surgeon who is operating on a living being. The information may be for example vital parameters of the living being, risk structures, or target positions for the operation. The information is portrayed for example using a display device of the information system, and the information system may include input means for the operation thereof. Because of the information portrayed by means of the display device, the attention of the surgeon must shift between the operation table and the display device, and possibly the input means.